prezenta_work/README_DEPENDENCIES.md

Prezenta App - Robust Dependency Management System

Overview

The app.py has been updated to include a comprehensive, self-contained dependency management system that automatically checks and installs required packages from a local repository. This makes the system completely offline-capable and resilient to network issues.

Key Features

🔧 Automatic Dependency Installation

• Self-contained: No need for separate launcher scripts or shell scripts
• Offline capability: Installs packages from local ./Files/reposytory directory
• Smart detection: Checks if packages are already installed before attempting installation
• Fallback mechanisms: Multiple installation methods (pip, apt, local wheels)

🛡️ Robust Error Handling

• Network resilience: Handles socket errors gracefully with file-based fallbacks
• Import safety: Safe import functions that don't crash the app
• Graceful degradation: App continues to work even if some optional features fail
• Comprehensive logging: All operations are logged for debugging

📦 Supported Packages

The system automatically manages these packages:

• rdm6300 - RFID reader library (critical)
• requests - HTTP library (critical)
• aiohttp - Async HTTP library (optional)
• flask - Web server for command interface (optional)
• gpiozero - GPIO control (falls back to dummy if not available)
• All required dependencies (urllib3, certifi, charset_normalizer, etc.)

How It Works

1. Startup Dependency Check

When the app starts, it:

1. Checks each required package using importlib.util.find_spec()
2. Identifies missing packages
3. Attempts installation from local wheel files in ./Files/reposytory
4. Falls back to pip/apt if needed
5. Continues execution even if some packages fail to install

2. Safe Import System

def safe_import(module_name, package_name=None):
    """Safely import a module with error handling"""

• Imports modules without crashing the app
• Returns None for missing modules
• Allows the app to adapt to available packages

3. Network Error Resilience

• Device hostname/IP saved to ./data/device_info.txt
• Automatically loads from file when socket errors occur
• Never crashes due to network resolution issues

4. Graceful Feature Degradation

• No Flask: Command server is disabled with warning
• No gpiozero: LED functions become print statements
• No aiohttp: Falls back to synchronous requests
• No network: Uses cached device information

Repository Structure

Required Files in ./Files/reposytory/:

├── rdm6300-0.1.1-py3-none-any.whl
├── requests-2.32.3-py3-none-any.whl
├── aiohttp-3.11.18-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl
├── flask-*.whl (optional)
├── urllib3-2.3.0-py3-none-any.whl
├── certifi-2025.1.31-py3-none-any.whl
├── charset_normalizer-3.4.1-py3-none-any.whl
├── idna-3.10-py3-none-any.whl
├── multidict-6.4.3-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl
├── aiosignal-1.3.2-py2.py3-none-any.whl
├── frozenlist-1.6.0-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl
├── attrs-25.3.0-py3-none-any.whl
├── yarl-1.20.0-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl
├── aiohappyeyeballs-2.6.1-py3-none-any.whl
└── propcache-0.3.1-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl

Installation Process

Automatic (Recommended)

Simply run the app - dependencies will be installed automatically:

cd /home/pi/Desktop/prezenta
python3 app.py

Manual Testing

Test the dependency system:

cd /home/pi/Desktop/prezenta
python3 test_dependencies.py

Folder Structure

The prezenta folder has been streamlined for maximum simplicity:

prezenta/
├── app.py                    # Main application (self-contained)
├── config.py                 # Configuration module  
├── test_dependencies.py      # Testing and validation script
├── README_DEPENDENCIES.md    # This documentation
├── data/                     # Application data
│   ├── device_info.txt       # Network configuration cache (auto-created)
│   ├── idmasa.txt           # Device identifier
│   └── tag.txt              # Backup data
└── Files/                    # Local package repository
    └── reposytory/          # Wheel files for offline installation
        ├── rdm6300-*.whl
        ├── requests-*.whl
        ├── aiohttp-*.whl
        └── ... (all dependencies)

Removed Files (No Longer Needed)

• launcher.py - App is now self-launching
• libraries.sh - Dependency installation integrated into app.py
• check_dependencies.py - Functionality moved to app.py

Features Added

1. Self-Installing Dependencies

• Checks all required packages on startup
• Installs missing packages from local repository
• No external network dependencies for package installation

2. Network Error Recovery

• Handles socket.gaierror gracefully
• Saves working network configuration to file
• Loads from file when network issues occur

3. Modular Feature Set

• Core RFID functionality always works
• Optional features (web interface, LEDs) degrade gracefully
• Clear status messages for all operations

4. Enhanced Logging

• Dependency check results logged
• Installation attempts logged
• Network fallback operations logged

Troubleshooting

Common Issues

1. "Repository not found"

   • Ensure ./Files/reposytory directory exists
   • Check that wheel files are present

2. "Permission denied during installation"

   • Script uses --break-system-packages flag
   • May need to run with appropriate permissions

3. "rdm6300 is required"

   • This is critical - app will exit if rdm6300 can't be installed
   • Check that rdm6300-0.1.1-py3-none-any.whl exists in repository

4. "Flask not available - Command server disabled"

   • Non-critical - RFID functionality continues to work
   • Install Flask manually if remote command capability is needed

Recovery Steps

1. Check repository: Ensure all wheel files are present
2. Test installation: Run python3 test_dependencies.py
3. Manual install: Install missing packages manually with pip
4. Check logs: Review console output for specific error messages

Benefits

1. Zero-configuration deployment: Just copy files and run
2. Offline operation: No internet required after initial setup
3. Fault tolerance: Continues working even with partial failures
4. Easy maintenance: All dependencies managed automatically
5. Clear diagnostics: Detailed status reporting for troubleshooting

Version History

• v2.4: Added robust dependency management and network error handling
• v2.3: Added remote command execution capabilities
• v2.2: Basic RFID and logging functionality

The system is now production-ready for deployment in environments with limited or no internet connectivity, providing maximum reliability and ease of deployment.